Lighthearted 'Love' has lost the old flame of 'Luv'; Love. Musical comedy by Jeffrey Sweet (book), Howard Marren (music), and Susan Birkenhead (lyrics). Based on ''Luv,'' by Murray Schisgal. Directed by Larry Fuller.

Can a 1964 Broadway satirical hit like ''Luv'' find success and happiness as a 1984 Off Broadway minimusical named ''Love''? The question is lightheartedly raised at the new Audrey Wood Theatre (in the new Jack Lawrence Theatre) on West 48th Street. Besides correcting playwright Murray Schisgal's mock misspelling, adaptor Jeffrey Sweet has allowed space for 19 musical numbers (including reprises) by composer Howard Marren and lyricist Susan Birkenhead.

The result is a musical farce about mixed-up love, friendship, marriage, and mores. Nathan Lane plays Harry, a wimpish loser rescued at from jumping off a New York City bridge by his old friend Milt (Stephen Vinovich), a superachiever. Yet prosperous as he is, Milt is not happy with his wife, Ellen (Judy Kaye), an intellectual beauty whose total recall would stun a computer. Milt wants to leave Ellen for a certain Linda.

Under Larry Fuller's zestful direction, the three talented musical-comedy artists play and sing and dance out the kaleidoscopic progression of dizzy relationships. Miss Birkenhead writes witty lyrics and some of Mr. Marren's tunes are pleasantly catchy.

As entertainment, however, ''Love'' misses the tautness and zany abandon of its original. (Nor can it quite be forgotten that ''Luv'' starred Alan Arkin, Eli Wallach, and Anne Jackson in a production directed by Mike Nichols.) Whatever the cause, the musical version tends to run out of steam before the would-be and would-not-be suicides clamber back onto designer Kevin Rupnik's sturdy bridge and take up their untidy lives.